ode45 with events returns event that did not happen

Hello,

i am using ode 45 with events and am having a problem i do not understand.

the problem is that i have defined the event in an event function and when i track the events values i clearly see that one goes to zero and the others do not so i am expacting one event as an output but i am recieving two event.

the other event clearly is not zero.

the codes i am using

ode45 options:

op_slip=odeset('reltol',tol,'abstol',tol,'Events',@events_slip);

ode 45 call:

[Tsl,Xsl,Tesl,Xesl,Iesl]=ode45(@sys_slip,Tsim,X0,op_slip);

tracking the events graphically:

the blue plot (data1) is the event that heppend and the red one (data2) is the event that the functions says that happened even thpough its value isnt 0

the output Iesl is [2;1]

can anyone shed some light on this problem? i am at a loss

thank you

[sivan levi]

Found out what went wrong.

if an event occurs at t=0 the event function does not terminate

from documantation under limitations:

"If a terminal event occurs during the first step of the integration, then the solver registers the event as nonterminal and continues integrating."